Ignition distributor of internal combustion engine

Abstract

A small, light and low cost ignition distributor having improved rotary detection accuracy can be realized. A pole piece having a pickup coil wound on it and bypass pole pieces having no pickup coil are arranged on the ignition distributor. The distance between the pole piece having a pickup coil and the bypass pole pieces is about 1.5 times as long as the distance between protrusions formed on the peripheral portion of a rotary body. When the distance between the pole piece having a pickup coil and a reluctor is minimum, the distance between the bypass pole pieces and the reluctor is maximum, and the linkage of magnetic flux of the pickup coil is maximum. When the distance between the pole piece having a pickup coil and the reluctor is maximum, the distance between the bypass pole pieces and the reluctor is minimum, and the magnetic flux bypasses the pole piece having a pickup coil and passes through the bypass pole pieces. Accordingly, the change of the magnetic flux passing through the pickup coil can be made to be large, and the change of the generated voltage can be made to be larger so that the rotary detection accuracy is improved.

What is claimed is: 
     
       1. An ignition distributor of an internal combustion engine comprising: magnetic flux generating means;   a rotary body rotating in proportion to the number of the rotations of the internal combustion engine, said rotary body having a plurality of protrusions on its peripheral portion;   a magnetic flux passing member arranged opposite to said rotary body, the magnetic flux from said magnetic flux generating means passing through said magnetic flux passing member; and   magnetic flux change detecting means for detecting the change of the magnetic flux passing through said magnetic flux passing member,   wherein said magnetic flux passing member includes a plurality of protruded portions disposed on the portion opposite to said rotary body, the plural protruded portions including a detection protruded portion having said magnetic flux change detecting means and bypass protruded portion having no magnetic flux change detecting means, the distance between the detection protruded portion and the bypass protruded portion in the circumferential of said rotary body being (n+m) times as long as the distance between the protrusions of said rotary body, the n being a natural number including 0, the m being a number which is larger than 0 and smaller than 1.   
     
     
       2. An ignition distributor according to claim 1, wherein said detection protruded portion and said bypass protruded portion are alternately arranged in the circumferential direction of said rotary body. 
     
     
       3. An ignition distributor according to claim 1, wherein said detection protruded portion and said bypass protruded portion are separately arranged in the axis direction of said rotary body. 
     
     
       4. An ignition distributor according to any one of claims 1 to 3, wherein the distance between said detection protruded portion and said bypass protruded portion is (n+0.5) times as long as the distance between the protrusions of said rotary body. 
     
     
       5. An ignition distributor according to any one of claim 1, wherein said magnetic flux change detecting means is composed of the pickup coil wound on said detection protruded portion. 
     
     
       6. An ignition distributor of an internal combustion engine comprising: magnetic flux generating means;   rotary bodies rotating in proportion to the number of the rotations of the internal combustion engine, said rotary bodies having a plurality of protrusions on these peripheral portions;   a magnetic flux passing member arranged opposite to said rotary bodies, the magnetic flux from said magnetic flux generating means passing through said magnetic flux passing member; and   magnetic flux change detecting means for detecting the change of the magnetic flux passing through said magnetic flux passing member,   wherein said plural rotary bodies are arranged in the direction of the rotary axis, said plural rotary bodies being one group of rotary bodies having protrusions spaced with each other at substantially same distance the peripheral direction and the other group of rotary bodies having protrusions each of which is arranged between the protrusions of one group of the rotary bodies as seen from the axis direction, the magnetic flux passing member including a plurality of protruded portions on the portions opposite to said rotary bodies, the plural protruded portions including a detection protruded portion having magnetic flux change detecting means and bypass protruded portion having no magnetic flux detecting means, said detection protruded portion being opposite to the peripheral portion of one group of the rotary bodies, the bypass protruded portion being opposite to the peripheral portion of the other group of said rotary bodies, the detection protruded portion and the bypass protruded portion being arranged on substantially same position as seen from the axis direction of said rotary bodies.   
     
     
       7. An ignition distributor according to claim 6, wherein the protrusions of the other group of the rotary bodies are positioned at substantially center portion between the protrusions of one group of the rotary bodies as seen from the axis direction. 
     
     
       8. An ignition distributor according to claim 6 or wherein said magnetic flux change detecting means is composed of the pickup coil wound on the protruded portion. 
     
     
       9. An ignition distributor of an internal combustion engine comprising: magnetic flux generating means;   a rotary body rotating in proportion to the number of the rotations of the internal combustion engine, said rotary body having a plurality of protrusions on its peripheral portion;   a magnetic flux passing member arranged opposite to said rotary body, the magnetic flux from said magnetic flux generating means passing through said magnetic flux passing member;   magnetic flux change detecting means for detecting the change of the magnetic flux passing through said magnetic flux passing member; and   composing means for composing the detection signals generated from said magnetic flux change detecting means,   wherein said magnetic flux passing member includes a plurality of protruded portions on the portion opposite to said rotary body, the plural protruded portions including a detection protruded portion and bypass protruded portion, said magnetic flux change detection means being arranged on all or a part of the detection protruded portions and the bypass protruded portions, the distance between the detection protruded portion and the bypass protruded portion in the circumferential of said rotary body being (n+m) times as long as the distance between the protrusions of said rotary body,the n being a natural number including 0, the m being a number which is larger than 0 and smaller than 1.   
     
     
       10. An ignition distributor according to claim 9, wherein said detection protruded portion and said bypass protruded portion are alternately arranged in the circumferential direction of said rotary body. 
     
     
       11. An ignition distributor according to claim 9, wherein said detection protruded portion and said bypass protruded portion are separately arranged in the axis direction of said rotary body. 
     
     
       12. An ignition distributor according to any one of claims 9 to 11, wherein the distance between said detection protruded portion and said bypass protruded portion is (n+0.5) times as long as the distance between the protrusions of said rotary body. 
     
     
       13. An ignition distributor according to claim 9, wherein said magnetic flux change detecting means includes a plurality of the first pickup coils wound on the detection protruded portions respectively, and a plurality of the second pickup coils wound on the bypass protruded portions respectively, the winding direction of the first pickup coils being equal to that of the second pickup coils, the composing means including the first adder for adding the voltages generated from the plural first pickup coils, the second adder for adding the voltages generated from the plural second pickup coils, and a differential amplifier for performing subtraction between the output voltages of the first and second adders and for amplifying the subtracted voltage. 
     
     
       14. An ignition distributor according to claim 9, wherein said magnetic flux change detecting means includes a plurality of the first pickup coils wound on the detection protruded portions respectively, and a plurality of the second pickup coils wound on the bypass protruded portions respectively, the winding direction of the first pickup coils being the reverse winding direction of the second pickup coils, the composing means including the first adder for adding the voltages generated from the plural first pickup coils, the second adder for adding the voltages generated from the plural second pickup coils, and a differential amplifier for adding the output voltage of the first adder to the output voltage of the second adder and for amplifying the added voltage. 
     
     
       15. An ignition distributor of an internal combustion engine comprising: magnetic flux generating means;   rotary bodies rotating in proportion to the number of the rotations of the internal combustion engine, said rotary bodies having a plurality of protrusions on these peripheral portions;   a magnetic flux passing member arranged opposite to said rotary bodies, the magnetic flux from said magnetic generating means passing through said magnetic flux passing member;   magnetic flux change detecting means for detecting the change of the magnetic flux passing through said magnetic flux passing member; and   a composing means for composing the detection signals generated from said magnetic flux detecting means,   wherein the plural rotary bodies are arranged in the direction of the rotary axis, said plural rotary bodies being one group of rotary bodies having protrusions spaced with each other at substantially same distance the peripheral direction, and the other group of rotary bodies having protrusions each of which is arranged between the protrusions of one group of rotary bodies as seen from the axis direction, said magnetic flux passing member including a plurality of protruded portions disposed on portions opposite to said rotary bodies, said plural protruded portions including a detection protruded portion and bypass protruded portion, said detection protruded portion being opposite to the peripheral portions of one group of rotary bodies, said bypass protruded portion being opposite to the peripheral portions of the other group of rotary bodies, said detection protruded portion and the bypass protruded portion being arranged on substantially same position as seen from the peripheral direction, said magnetic flux change detecting means being arranged on all or a part of the detection protruded portions and the bypass protruded portions.   
     
     
       16. An ignition distributor according to claim 15, wherein the protrusions of the other group of rotary bodies are positioned at substantially center portion between the protrusions of one group of rotary bodies as seen from the axis direction. 
     
     
       17. An ignition distributor according to claim 15 or 16, wherein said magnetic flux change detecting means includes a plurality of the first pickup coils wound on the detection protruded portion respectively and a plurality of the second pickup coils wound on the bypass protruded portion respectively, the winding direction of the first pickup coils being equal to that of the second pickup coils, said composing means including the first adder for adding the voltages generated from the plural first pickup coils, the second adder for adding the voltages generated from the plural second pickup coils, and a differential amplifier for performing subtraction between the output voltages of the first and second adders and for amplifying the subtracted voltage. 
     
     
       18. An ignition distributor according to claim 15 or 16, wherein said magnetic flux change detecting means includes a plurality of the first pickup coils wound on the detection protruded portions respectively, and a plurality of the second pickup coils wound on the bypass protruded portions respectively, the winding direction of the first pickup coils being the reverse winding direction of the second pickup coils, said composing means including the first adder for adding the voltages generated from the plural first pickup coils, the second adder for adding the voltages generated from the plural second pickup coils, and an amplifier for adding the output voltage of the first adder to the output voltage of the second adder and for amplifying the added voltage. 
     
     
       19. An ignition distributor according to any one of claims 1, 6, 9 and 15, wherein said detection protruded portions and the bypass protruded portions are integrally fixed by a guide member made of a non-magnetic substance. 
     
     
       20. An ignition distributor of an internal combustion engine comprising: a permanent magnet for generating magnetic flux;   a magnetic flux passing member, wherein the magnetic flux passes through and one end of the passing member contacts to said permanent magnet;   a rotary body having a plurality of protrusions, which are opposite to the other end of the magnetic flux passing member, disposed on its peripheral portion;   a shaft for rotating said rotary body in proportion to the number of the rotations of the internal combustion engine;   a stator one end of which is opposite-to said shaft and the other end is contacted to said permanent magnet; and   a magnetic flux change detecting means,   wherein the closed magnetic circuit is formed of said permanent magnet, said flux passing member, said rotary body, said shaft, and said stator, the quantity of the magnetic flux passing through said magnetic flux passing member being changed by the rotation of said rotary body, the magnetic flux passing member including a plurality of protruded portions on the opposite to said rotary body, a plurality of protruded portions being formed on the other end of said magnetic flux passing member, the plural protruded portions including detection protruded portions having flux change detecting means and bypass protruded portions having no magnetic flux change detecting means, the distance between said detection protruded portion and said bypass protruded portion in the circumferential of said rotary body being (n+m) times as long as the distance between the protrusions of said rotary body, the n being a natural number including 0, the m being a number which is larger than 0 and smaller than 1.